There is a way to instance two rigid body objects with hinge constraint between then using AN?
When you instance the object using the Copy Full Object option of the Instancer node, you are copying the constraints of the source object to all instances. And the constraints data for all instances will be the same. So all you have to do in this case is to update the data of the constraints. Consider the following example where we instance a group of cubes having a Damped Track constraint, after instancing, all cubes point to the icosphere because it is the target.



What we can do now is instance the icosphere and set the instances as the targets of the constraints of the cubes. The Object Attribute Output node can be used.